scholarly journals Effect of -O- on Water Molecule Adsorption and Adsorption Mechanism of Lignite and Coke

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Xue Bai ◽  
Yue Yin Song ◽  
Ying Yue Teng ◽  
Wen Lu Zhang ◽  
Yin Min Song ◽  
...  
Keyword(s):  
Water Molecule ◽  
1H Nmr ◽  
Adsorption Mechanism ◽  
Adsorbed Water ◽  
Proton Nuclear Magnetic Resonance ◽  
Special Role ◽  
Adsorption Mechanisms ◽  
Molecule Adsorption ◽  
Different Temperatures ◽  
Moisture Desorption

The high moisture content of lignite restricts its extensive and efficient use. Furthermore, the reabsorption of lignite is also a factor that affects lignite spontaneous combustion. Therefore, it is of great importance to study the process and mechanism of water molecule desorption and adsorption on lignite and coke (25–950°C) to achieve the clean and efficient utilization of lignite and environmental protection. Proton nuclear magnetic resonance (1H-NMR), thermogravimetric analysis, and other techniques were used in this study to explore the water molecule absorption and desorption processes of lignite pyrolysis at different temperatures (25–950°C) and the special contributions of ether bonds to water molecule adsorption. A mechanism of lignite water molecule adsorption was proposed. The results showed that ether bonds played a special role in the water molecule adsorption by pyrolyzed lignite. The ether bond content was greater in the coal samples at 300 and 950°C, which changed the trend of lignite water molecule absorption and the distribution of water (T2) detected in the 1H-NMR experiments and delayed the escape of water molecules during moisture desorption. The total amount of adsorbed water decreased first and then increased in the coal samples as the pyrolysis temperature increased. However, the maximum adsorption interactions of each coal sample increased first and then decreased. This was the result of the interactions between the pores and the oxygen-containing functional groups. Based on the above analysis, water molecule adsorption mechanism models of lignite and coke were constructed. This study offers a new approach for investigating the water molecule adsorption and adsorption mechanisms of lignite and coke.

scholarly journals 1H NMR investigation of distal mutant deoxy myoglobins. Interpretation of proximal His contact shifts in terms of a localized distal water molecule.

1994 ◽  
Vol 269 (47) ◽  
pp. 29629-29635
Author(s):  
G N La Mar ◽  
F Dalichow ◽  
X Zhao ◽  
Y Dou ◽  
M Ikeda-Saito ◽  
...  
Keyword(s):  
Water Molecule ◽  
1H Nmr

Adsorption mechanism of NH3, NO, and O2 molecules over FexOy/AC catalyst surface: a DFT-D3 study

2021 ◽  
Author(s):  
Chaoyue Xie ◽  
Yunlan Sun ◽  
Baozhong Zhu ◽  
Weiyi Song ◽  
Minggao Xu
Keyword(s):  
Activated Carbon ◽  
Adsorption Mechanism ◽  
Catalyst Surface ◽  
Specific Adsorption ◽  
Adsorption Mechanisms ◽  
Iron Based ◽  
Iron Based Catalysts ◽  
Supported Iron ◽  
Denox Efficiency

Activated carbon-supported iron-based catalysts (FexOy/AC) show excellent deNOx efficiency. However, the specific adsorption mechanisms of NH3, NO, and O2 molecules on their surfaces are still unknown. In this study, the...

scholarly journals Neuroendocrine Neoplasms: Identification of Novel Metabolic Circuits of Potential Diagnostic Utility

Cancers ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 374
Author(s):  
Beatriz Jiménez ◽  
Mei Ran Abellona U ◽  
Panagiotis Drymousis ◽  
Michael Kyriakides ◽  
Ashley K. Clift ◽  
...  
Keyword(s):  
1H Nmr ◽  
Cancer Metabolism ◽  
Proton Nuclear Magnetic Resonance ◽  
Neuroendocrine Neoplasms ◽  
Resonance Spectroscopy ◽  
Diagnostic Utility ◽  
Signalling Molecules ◽  
Prognostic Accuracy ◽  
Diagnostic Potential ◽  
Healthy Control

The incidence of neuroendocrine neoplasms (NEN) is increasing, but established biomarkers have poor diagnostic and prognostic accuracy. Here, we aim to define the systemic metabolic consequences of NEN and to establish the diagnostic utility of proton nuclear magnetic resonance spectroscopy (1H-NMR) for NEN in a prospective cohort of patients through a single-centre, prospective controlled observational study. Urine samples of 34 treatment-naïve NEN patients (median age: 59.3 years, range: 36–85): 18 had pancreatic (Pan) NEN, of which seven were functioning; 16 had small bowel (SB) NEN; 20 age- and sex-matched healthy control individuals were analysed using a 600 MHz Bruker 1H-NMR spectrometer. Orthogonal partial-least-squares-discriminant analysis models were able to discriminate both PanNEN and SBNEN patients from healthy control (Healthy vs. PanNEN: AUC = 0.90, Healthy vs. SBNEN: AUC = 0.90). Secondary metabolites of tryptophan, such as trigonelline and a niacin-related metabolite were also identified to be universally decreased in NEN patients, while upstream metabolites, such as kynurenine, were elevated in SBNEN. Hippurate, a gut-derived metabolite, was reduced in all patients, whereas other gut microbial co-metabolites, trimethylamine-N-oxide, 4-hydroxyphenylacetate and phenylacetylglutamine, were elevated in those with SBNEN. These findings suggest the existence of a new systems-based neuroendocrine circuit, regulated in part by cancer metabolism, neuroendocrine signalling molecules and gut microbial co-metabolism. Metabonomic profiling of NEN has diagnostic potential and could be used for discovering biomarkers for these tumours. These preliminary data require confirmation in a larger cohort.

scholarly journals Vapor Phase Modification for Selective Enrichment of Grafted Styrene/Acrylonitrile onto Carbon Nanotubes Via ATRP

Processes ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 459
Author(s):  
Maryam Azadbakht ◽  
Elnaz Esmizadeh ◽  
Ali Vahidifar ◽  
Tizazu H. Mekonnen ◽  
Mehdi Salami-Kalajahi
Keyword(s):  
Carbon Nanotubes ◽  
1H Nmr ◽  
Vapor Phase ◽  
Proton Nuclear Magnetic Resonance ◽  
Acid Vapor ◽  
Selective Enrichment ◽  
Pristine Mwcnts ◽  
Morphological Studies ◽  
Phase Oxidation ◽  
Multi Walled Carbon Nanotubes

Nitric acid vapor phase oxidation of multi-walled carbon nanotubes (MWCNTs) was proposed as a promising technique to fabricate poly styrene-co-acrylonitrile (SAN)-grafted-CNTs via atom transfer radical polymerization (ATRP). The in-situ ATRP grafting approach was successfully employed to graft polystyrene (PS), SAN and polyacrylonitrile (PAN), onto the convex surfaces of pristine MWCNTs (PCNT) and acid-functionalized MWCNTs (FCNT). Fourier transform infrared spectroscopy (FTIR), proton nuclear magnetic resonance (1H-NMR), and thermogravimetric analysis (TGA) confirmed the effectiveness of the modification via the ATRP grafting approach. The molar composition of acrylonitrile in the synthesized copolymer on the surface of CNTs for an FCNTs was calculated to be about 80% and 67.5% by 1H-NMR and TGA respectively, whereas the value is lower for PCNTs. Morphological studies showed that SAN-grafted FCNTs exhibit rougher surface morphology compared to the SAN-grafted PCNTs. Moreover, the higher diameter of the FCNTs indicated the higher polymer content, which was coated onto CNTs functionalized by vapor-phase oxidation. Therefore, the vapor phase oxidation strategy employed in this study could be utilized as a general method to prepare CNTs which can serve as an ATRP macroinitiator for the fabrication of various polymer grafted CNTs.

Polyhydroxyalkanoate quantification in organic wastes and pure cultures using a single-step extraction and 1H NMR analysis

2012 ◽  
Vol 66 (5) ◽  
pp. 1000-1006 ◽  
Author(s):  
Elisabeth Linton ◽  
Asif Rahman ◽  
Sridhar Viamajala ◽  
Ronald C. Sims ◽  
Charles D. Miller
Keyword(s):  
1H Nmr ◽  
Azotobacter Vinelandii ◽  
Nile Blue ◽  
Agricultural Waste ◽  
Accurate Method ◽  
Single Step ◽  
Proton Nuclear Magnetic Resonance ◽  
Copolymer Composition ◽  
Nmr Analysis ◽  
Nmr Method

In this study, a proton nuclear magnetic resonance (1H NMR) method was developed to quantitatively analyze polyhydroxyalkanoate (PHA) content in Cupriavidus necator H16, Azotobacter vinelandii AvOP, and mixed microbial cultures from the effluent of an agricultural waste treatment anaerobic digester. In contrast to previous methods, a single-step PHA extractive method using deuterated chloroform was established, thereby facilitating direct 1H NMR analysis. The accuracy of the method was verified through comparison with well-established gas chromatography (GC) methanolysis techniques. Nile blue fluorescence staining was also carried out to serve as an independent and qualitative indicator of intracellular PHA content. The results indicate that the 1H NMR method is appropriate for rapid and non-destructive quantification of overall PHA content and determination of PHA copolymer composition in a variety of cultures. Notably, this technique was effective in measuring PHA content in full-strength waste samples where high concentrations of background impurities and organic compounds are present. The straightforward procedures minimize error-introducing steps, require less time and materials, and result in an accurate method suitable for routine analyses.

scholarly journals Fingerprinting Acute Digestive Diseases by Untargeted NMR Based Metabolomics

2018 ◽  
Vol 19 (11) ◽  
pp. 3288 ◽  
Author(s):  
Panteleimon Takis ◽  
Antonio Taddei ◽  
Riccardo Pini ◽  
Stefano Grifoni ◽  
Francesca Tarantini ◽  
...  
Keyword(s):  
Abdominal Pain ◽  
1H Nmr ◽  
Intestinal Ischemia ◽  
Principal Component ◽  
Disease Diagnosis ◽  
Proton Nuclear Magnetic Resonance ◽  
Mechanical Obstruction ◽  
Symptomatic Gallstones ◽  
Symptom Group ◽  
Upper Abdominal

Precision medicine may significantly contribute to rapid disease diagnosis and targeted therapy, but relies on the availability of detailed, subject specific, clinical information. Proton nuclear magnetic resonance (1H–NMR) spectroscopy of body fluids can extract individual metabolic fingerprints. Herein, we studied 64 patients admitted to the Florence main hospital emergency room with severe abdominal pain. A blood sample was drawn from each patient at admission, and the corresponding sera underwent 1H–NMR metabolomics fingerprinting. Unsupervised Principal Component Analysis (PCA) analysis showed a significant discrimination between a group of patients with symptoms of upper abdominal pain and a second group consisting of patients with diffuse abdominal/intestinal pain. Prompted by this observation, supervised statistical analysis (Orthogonal Partial Least Squares–Discriminant Analysis (OPLS-DA)) showed a very good discrimination (>90%) between the two groups of symptoms. This is a surprising finding, given that neither of the two symptoms points directly to a specific disease among those studied here. Actually herein, upper abdominal pain may result from either symptomatic gallstones, cholecystitis, or pancreatitis, while diffuse abdominal/intestinal pain may result from either intestinal ischemia, strangulated obstruction, or mechanical obstruction. Although limited by the small number of samples from each of these six conditions, discrimination of these diseases was attempted. In the first symptom group, >70% discrimination accuracy was obtained among symptomatic gallstones, pancreatitis, and cholecystitis, while for the second symptom group >85% classification accuracy was obtained for intestinal ischemia, strangulated obstruction, and mechanical obstruction. No single metabolite stands up as a possible biomarker for any of these diseases, while the contribution of the whole 1H–NMR serum fingerprint seems to be a promising candidate, to be confirmed on larger cohorts, as a first-line discriminator for these diseases.

The decomposition of aliphatic N-nitro amines in aqueous sulfuric acid. Bisulfate as a nucleophile

1996 ◽  
Vol 74 (10) ◽  
pp. 1774-1778 ◽  
Author(s):  
Robin A. Cox
Keyword(s):  
Sulfuric Acid ◽  
Water Molecule ◽  
Rate Constants ◽  
Activation Parameters ◽  
Standard State ◽  
Aqueous Sulfuric Acid ◽  
Alkyl Groups ◽  
Different Temperatures ◽  
State Rate ◽  
Acid Catalyzed

In aqueous sulfuric acid, aliphatic N-nitro amines decompose to N2O and alcohols. An excess acidity analysis of the observed rate constants for the reaction shows that free carbocations are not formed. The reaction is an acid-catalyzed SN2 displacement from the protonated aci-nitro tautomer, the nucleophile being a water molecule at acidities below 82–85% H2SO4, and a bisulfate ion at higher acidities. Bisulfate is the poorer nucleophile by a factor of about 1000. Twelve compounds were studied, of which results obtained for nine at several different temperatures enabled calculation of activation parameters for both nucleophiles. The reaction appears to be mainly enthalpy controlled. The intercept standard-state rate constants are well correlated by the σ* values for the alkyl groups; the slopes are negative, with a more negative value for the slower bisulfate reaction. Interestingly the m≠m* slopes also correlate with σ*, although the scatter is bad. Key words: N-nitro amines, excess acidity, bisulfate, nucleophiles, acid-catalyzed, kinetics.

scholarly journals ISOLATION OF 2-CHLOROBENZIMIDAZOLE FROM MELIA DUBIA LEAF EXTRACT AND ITS STRUCTURAL CHARACTERISATION

2017 ◽  
Vol 9 (10) ◽  
pp. 67 ◽  
Author(s):  
G. Dayana Jeyaleela ◽  
S. Irudaya Monisha ◽  
J. Rosaline Vimala ◽  
A. Anitha Immaculate
Keyword(s):  
Mass Spectrometry ◽  
1H Nmr ◽  
Research Work ◽  
Proton Nuclear Magnetic Resonance ◽  
Resonance Spectroscopy ◽  
Ft Ir ◽  
Uv Visible ◽  
Isolated Compound ◽  
Promising Source

Objective: Natural products from medicinal plants, either as isolated compounds or as standardized plant extracts exhibit promising source of medicinal activity against various diseases. The aim of the present work was to make an attempt of isolation of bioactive principle and characterization of the isolated compound, from the medicinal plant Melia dubaiMethods: The extraction was done by a cold percolation method and the compound was separated and isolated by chromatography technique such as a thin layer chromatography (TLC), column chromatography and high-performance liquid chromatography (HPLC). The isolated compound was crystallized and the structural characterization of the isolated compound was made using UV-Visible, FT-IR, 1H-NMR, GC-MS and MS techniques which confirmed the structure of the isolated compound.Results: The separated and isolated compound was characterized by both physical and spectral methods like Ultraviolet-Visible spectroscopy (UV-Visible), Fourier transform infrared spectroscopy (FT-IR), Proton Nuclear Magnetic Resonance Spectroscopy (1H-NMR), Gas chromatography-mass spectrometry (GC-MS), and Mass spectrometry(MS). Based on the studies, organizational characteristics of one bioactive principle were deciphered. The results revealed that the isolated species is 2-chlorobenzimidazole and it agreed well with the reported value and spectra for 2-chlorobenzimidazole.Conclusion: The above results obtained in this research work clearly indicated the promising occurrence of 2-chlorobenzimidazole in Media dubia plant leaves. The future scope of these studies may guide us to view the biological activity of the isolated compound.

scholarly journals Distinct Influence of Omega-3 Fatty Acids on the Plasma Metabolome of Healthy Older Adults

2019 ◽  
Vol 75 (5) ◽  
pp. 875-884 ◽  
Author(s):  
Souzana-Eirini Xyda ◽  
Ivan Vuckovic ◽  
Xuan-Mai Petterson ◽  
Surendra Dasari ◽  
Antigoni Z Lalia ◽  
...  
Keyword(s):  
Older Adults ◽  
Fatty Acids ◽  
1H Nmr ◽  
Biological Effects ◽  
Density Lipoprotein ◽  
Proton Nuclear Magnetic Resonance ◽  
Omega 3 ◽  
Pufa Supplementation ◽  
Healthy Older Adults ◽  
Insight Into

Abstract Omega-3 polyunsaturated fatty acids (n3-PUFA) are well recognized for their potent triglyceride-lowering effects, but the potential influence of these bioactive lipids on other biological processes, particularly in the context of healthy aging, remains unknown. With the goal of gaining new insight into some less well-characterized biological effects of n3-PUFAs in healthy older adults, we performed metabolomics of fasting peripheral blood plasma collected from 12 young adults and 12 older adults before and after an open-label intervention of n3-PUFA (3.9 g/day, 2.7 g eicosapentaenoic [EPA], 1.2 g docosahexaenoic [DHA]). Proton nuclear magnetic resonance (1H-NMR) based lipoprotein subclass analysis revealed the expected reduction in total triglyceride (TG), but also demonstrated that n3-PUFA supplementation reduced very low-density lipoprotein (VLDL) particle number, modestly increased high-density lipoprotein (HDL) cholesterol, and shifted the composition of HDL subclasses. Further metabolite profiling by 1H-NMR and mass spectrometry revealed pronounced changes in phospholipids, cholesterol esters, diglycerides, and triglycerides following n3-PUFA supplementation. Furthermore, significant changes in hydroxyproline, kynurenine, and 3-carboxy-4-methyl-5-propyl-2-furanpropionic acid (CMPF) following n3-PUFA supplementation provide further insight into some less well-recognized biological effects of n3-PUFA supplementation, including possible effects on protein metabolism, the kynurenine pathway, and glucose metabolism.

Proton Nuclear Magnetic Resonance (1H NMR) profiling of isolated organs in the snail Helix aspersa maxima

2019 ◽  
Vol 105 ◽  
pp. 177-187 ◽  
Author(s):  
Devalckeneer Aude ◽  
Bouviez Marion ◽  
Conotte Raphaël ◽  
Jean-Marie Colet
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
1H Nmr ◽  
Helix Aspersa ◽  
Proton Nuclear Magnetic Resonance ◽  
Isolated Organs ◽  
Snail Helix Aspersa ◽  
Helix Aspersa Maxima ◽  
Nuclear Magnetic
Sign in / Sign up

Export Citation Format

Share Document